Ground check and changing gravityScale

I am making a Side-scrolling 2d game and would like to make the player moving on the slope without sliding.

I tried to realize this by setting the Rigidbody2D.gravityScale to 0 when the player touches the ground and 1 when the player leaves the ground.

     void OnTriggerEnter2D(Collider2D Coll)
     {
         if (Coll.gameObject.tag == "Ground")
         {
             Rigidbody2D rb = GetComponent<Rigidbody2D>();
             rb.gravityScale = 0;
         }
     }
 
     void onTriggerExit2D(Collider2D Coll)
     {
         if (Coll.gameObject.tag == "Ground")
         {
             Rigidbody2D rb = GetComponent<Rigidbody2D>();
             rb.gravityScale = 1;
         }
     }

The default gravityScale is 1. The program successfully changes the gravityScale to 0 while touching the ground but never changes back to 1 when the player leaves the ground.

Is there any problem with my code? Or is there any better solution?